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Author Horváth, G.; Blahó, M.; Kriska, G.; Hegedüs, R.; Gerics, B.; Farkas, R.; Åkesson, S.
Title An unexpected advantage of whiteness in horses: the most horsefly-proof horse has a depolarizing white coat Type Journal Article
Year 2010 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal
Volume (down) 277 Issue 1688 Pages 1643-1650
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Abstract White horses frequently suffer from malign skin cancer and visual deficiencies owing to their high sensitivity to the ultraviolet solar radiation. Furthermore, in the wild, white horses suffer a larger predation risk than dark individuals because they can more easily be detected. In spite of their greater vulnerability, white horses have been highly appreciated for centuries owing to their natural rarity. Here, we show that blood-sucking tabanid flies, known to transmit disease agents to mammals, are less attracted to white than dark horses. We also demonstrate that tabanids use reflected polarized light from the coat as a signal to find a host. The attraction of tabanids to mainly black and brown fur coats is explained by positive polarotaxis. As the host's colour determines its attractiveness to tabanids, this parameter has a strong influence on the parasite load of the host. Although we have studied only the tabanid–horse interaction, our results can probably be extrapolated to other host animals of polarotactic tabanids, as the reflection–polarization characteristics of the host's body surface are physically the same, and thus not species-dependent.
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Call Number Equine Behaviour @ team @ Serial 5702
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Author Magat, M.; Brown, C.
Title Laterality enhances cognition in Australian parrots Type Journal Article
Year 2009 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal Proc. Roy. Soc. Lond. B Biol. Sci.
Volume (down) 276 Issue 1676 Pages 4155-4162
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Abstract Cerebral lateralization refers to the division of information processing in either hemisphere of the brain and is a ubiquitous trait among vertebrates and invertebrates. Given its widespread occurrence, it is likely that cerebral lateralization confers a fitness advantage. It has been hypothesized that this advantage takes the form of enhanced cognitive function, potentially via a dual processing mechanism whereby each hemisphere can be used to process specific types of information without contralateral interference. Here, we examined the influence of lateralization on problem solving by Australian parrots. The first task, a pebble-seed discrimination test, was designed for small parrot species that feed predominately on small seeds, which do not require any significant manipulation with the foot prior to ingestion. The second task, a string-pull problem, was designed for larger bodied species that regularly use their feet to manipulate food objects. In both cases, strongly lateralized individuals (those showing significant foot and eye biases) outperformed less strongly lateralized individuals, and this relationship was substantially stronger in the more demanding task. These results suggest that cerebral lateralization is a ubiquitous trait among Australian parrots and conveys a significant foraging advantage. Our results provide strong support for the enhanced cognitive function hypothesis.
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Call Number Equine Behaviour @ team @ Serial 5380
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Author Dickens, M.J.; Delehanty, D.J.; Romero, L.M.
Title Stress and translocation: alterations in the stress physiology of translocated birds Type Journal Article
Year 2009 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal
Volume (down) 276 Issue 1664 Pages 2051-2056
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Abstract Translocation and reintroduction have become major conservation actions in attempts to create self-sustaining wild populations of threatened species. However, avian translocations have a high failure rate and causes for failure are poorly understood. While ‘stress’ is often cited as an important factor in translocation failure, empirical evidence of physiological stress is lacking. Here we show that experimental translocation leads to changes in the physiological stress response in chukar partridge, Alectoris chukar. We found that capture alone significantly decreased the acute glucocorticoid (corticosterone, CORT) response, but adding exposure to captivity and transport further altered the stress response axis (the hypothalamic–pituitary–adrenal axis) as evident from a decreased sensitivity of the negative feedback system. Animals that were exposed to the entire translocation procedure, in addition to the reduced acute stress response and disrupted negative feedback, had significantly lower baseline CORT concentrations and significantly reduced body weight. These data indicate that translocation alters stress physiology and that chronic stress is potentially a major factor in translocation failure. Under current practices, the restoration of threatened species through translocation may unwittingly depend on the success of chronically stressed individuals. This conclusion emphasizes the need for understanding and alleviating translocation-induced chronic stress in order to use most effectively this important conservation tool.
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Call Number Equine Behaviour @ team @ Serial 5582
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Author Williams, N.
Title Evolutionary psychologists look for roots of cognition Type
Year 1997 Publication Science (New York, N.Y.) Abbreviated Journal Science
Volume (down) 275 Issue 5296 Pages 29-30
Keywords Animals; *Behavior, Animal; Birds; *Cognition; *Evolution; Female; Humans; Macaca mulatta/psychology; Male; Memory; Reward; *Social Sciences
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ISSN 0036-8075 ISBN Medium
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Notes PMID:8999531 Approved no
Call Number Equine Behaviour @ team @ Serial 2845
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Author Schultz, W.; Dayan, P.; Montague, P.R.
Title A Neural Substrate of Prediction and Reward Type Journal Article
Year 1997 Publication Science Abbreviated Journal
Volume (down) 275 Issue 5306 Pages 1593-1599
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Abstract The capacity to predict future events permits a creature to detect, model, and manipulate the causal structure of its interactions with its environment. Behavioral experiments suggest that learning is driven by changes in the expectations about future salient events such as rewards and punishments. Physiological work has recently complemented these studies by identifying dopaminergic neurons in the primate whose fluctuating output apparently signals changes or errors in the predictions of future salient and rewarding events. Taken together, these findings can be understood through quantitative theories of adaptive optimizing control.
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Call Number Equine Behaviour @ team @ Serial 5749
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Author Webster, M.M.; Laland, K.N.
Title Social learning strategies and predation risk: minnows copy only when using private information would be costly Type Journal Article
Year 2008 Publication Proc Biol Sci Abbreviated Journal Proc. R. Soc. Lond. B
Volume (down) 275 Issue 1653 Pages 2869-2876
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Abstract Animals can acquire information from the environment privately, by sampling it directly, or socially, through learning from others. Generally, private information is more accurate, but expensive to acquire, while social information is cheaper but less reliable. Accordingly, the 'costly information hypothesis' predicts that individuals will use private information when the costs associated with doing so are low, but that they should increasingly use social information as the costs of using private information rise. While consistent with considerable data, this theory has yet to be directly tested in a satisfactory manner. We tested this hypothesis by giving minnows (Phoxinus phoxinus) a choice between socially demonstrated and non-demonstrated prey patches under conditions of low, indirect and high simulated predation risk. Subjects had no experience (experiment 1) or prior private information that conflicted with the social information provided by the demonstrators (experiment 2). In both experiments, subjects spent more time in the demonstrated patch than in the non-demonstrated patch, and in experiment 1 made fewer switches between patches, when risk was high compared with when it was low. These findings are consistent with the predictions of the costly information hypothesis, and imply that minnows adopt a 'copy-when-asocial-learning-is-costly' learning strategy.
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Call Number Equine Behaviour @ team @ Serial 6196
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Author Bonnie, K.E.; Horner, V.; Whiten, A.; de Waal, F.B.M.
Title Spread of arbitrary conventions among chimpanzees: a controlled experiment Type Journal Article
Year 2007 Publication Proceedings. Biological sciences / The Royal Society Abbreviated Journal Proc Biol Sci
Volume (down) 274 Issue 1608 Pages 367-372
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Abstract Wild chimpanzees (Pan troglodytes) have a rich cultural repertoire--traditions common in some communities are not present in others. The majority of reports describe functional, material traditions, such as tool use. Arbitrary conventions have received far less attention. In the same way that observations of material culture in wild apes led to experiments to confirm social transmission and identify underlying learning mechanisms, experiments investigating how arbitrary habits or conventions arise and spread within a group are also required. The few relevant experimental studies reported thus far have relied on cross-species (i.e. human-ape) interaction offering limited ecological validity, and no study has successfully generated a tradition not involving tool use in an established group. We seeded one of two rewarded alternative endpoints to a complex sequence of behaviour in each of two chimpanzee groups. Each sequence spread in the group in which it was seeded, with many individuals unambiguously adopting the sequence demonstrated by a group member. In one group, the alternative sequence was discovered by a low ranking female, but was not learned by others. Since the action-sequences lacked meaning before the experiment and had no logical connection with reward, chimpanzees must have extracted both the form and benefits of these sequences through observation of others.
Address Living Links, Yerkes National Primate Research Center, Atlanta, GA 30329, USA. kebonni@emory.edu
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ISSN 0962-8452 ISBN Medium
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Notes PMID:17164200 Approved no
Call Number refbase @ user @ Serial 157
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Author Wittig, R.M.; Crockford, C.; Wikberg, E.; Seyfarth, R.M.; Cheney, D.L.
Title Kin-mediated reconciliation substitutes for direct reconciliation in female baboons Type Journal Article
Year 2007 Publication Proceedings. Biological sciences / The Royal Society Abbreviated Journal Proc Biol Sci
Volume (down) 274 Issue 1613 Pages 1109-1115
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Abstract It has been hypothesized that group-living mammals engage in reconciliation (post-conflict affiliation between former opponents) to reduce the disruptive costs of aggression and restore opponents' tolerance to baseline levels. Recipients of aggression are sometimes reluctant to tolerate the proximity of a recent opponent, however, in apparent fear that aggression will be renewed. In such cases, reconciliatory behaviour by the aggressor's close kin may substitute for direct reconciliation. We describe a playback experiment with free-ranging baboons (Papio hamadryas ursinus) that examines whether friendly behaviour by the aggressor's kin can substitute for direct reconciliation by the aggressor herself. In the test condition, female subjects who had recently been threatened heard the friendly grunt of one of their aggressor's relatives, mimicking kin-mediated vocal reconciliation. In the control condition, subjects heard the grunt of a dominant female from a different matriline. Subjects responded significantly more strongly in test than in control trials. Moreover, in the next hour they were significantly more likely to tolerate the proximity of both their aggressor and the relative whose grunt they had heard. In contrast, subjects' behaviour towards both control females and other members of their aggressor's matriline was unaffected. We conclude that kin-mediated vocal reconciliation can substitute for direct reconciliation in baboons.
Address Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA
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Notes PMID:17301022 Approved no
Call Number refbase @ user @ Serial 342
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Author Arlettaz, R.; Patthey, P.; Baltic, M.; Leu, T.; Schaub, M.; Palme, R.; Jenni-Eiermann, S.
Title Spreading free-riding snow sports represent a novel serious threat for wildlife Type Journal Article
Year 2007 Publication Proceedings. Biological Sciences / The Royal Society Abbreviated Journal Proc Biol Sci
Volume (down) 274 Issue 1614 Pages 1219-1224
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Abstract Stress generated by humans on wildlife by continuous development of outdoor recreational activities is of increasing concern for biodiversity conservation. Human disturbance often adds to other negative impact factors affecting the dynamics of vulnerable populations. It is not known to which extent the rapidly spreading free-riding snow sports actually elicit detrimental stress (allostatic overload) upon wildlife, nor what the potential associated fitness and survival costs are. Using a non-invasive technique, we evaluated the physiological stress response induced by free-riding snow sports on a declining bird species of Alpine ecosystems. The results of a field experiment in which radiomonitored black grouse (Tetrao tetrix) were actively flushed from their snow burrows once a day during four consecutive days showed an increase in the concentration of faecal stress hormone (corticosterone) metabolites after disturbance. A large-scale comparative analysis across the southwestern Swiss Alps indicated that birds had higher levels of these metabolites in human-disturbed versus undisturbed habitats. Disturbance by snow sport free-riders appears to elevate stress, which potentially represents a new serious threat for wildlife. The fitness and survival costs of allostatic adjustments have yet to be estimated.
Address Zoological Institute, Division of Conservation Biology, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland. raphael.arlettaz@nat.unibe.ch
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ISSN 0962-8452 ISBN Medium
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Notes PMID:17341459 Approved no
Call Number Equine Behaviour @ team @ Serial 4075
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Author Mesterton-Gibbons, M.; Gavrilets, S.; Gravner, J.; Akçay, E.
Title Models of coalition or alliance formation Type Journal Article
Year 2011 Publication Journal of Theoretical Biology Abbreviated Journal J. Theor. Biol.
Volume (down) 274 Issue 1 Pages 187-204
Keywords Game theory; Cooperation
Abstract More than half a century has now elapsed since coalition or alliance formation theory (CAFT) was first developed. During that time, researchers have amassed a vast amount of detailed and high-quality data on coalitions or alliances among primates and other animals. But models have not kept pace, and more relevant theory is needed. In particular, even though CAFT is primarily an exercise in polyadic game theory, game theorists have devoted relatively little attention to questions that motivate field research, and much remains largely unexplored. The state of the art is both a challenge and an opportunity. In this review we describe a variety of game-theoretic and related modelling approaches that have much untapped potential to address the questions that field biologists ask.
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ISSN 0022-5193 ISBN Medium
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Call Number Equine Behaviour @ team @ Serial 5322
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